Historical Perspective: A. H. Mehregan and D. A. Mehregan, 1993

 
In 1993, in an article about "Malignant melanoma in childhood," A. H. Mehregan and D. A. Mehregan49 reported on six children 14 years of age and younger with melanoma. The six lesions were found in their file of 850,000 consecutive biopsy specimens of skin and of sections of tissue sent in consultation to their laboratory over a period of 32 years. In addition to melanoma, one child had neurocutaneous melanosis and another had a large congenital nevus. The Mehregans considered one melanoma to be superficial spreading in association with a dysplastic nevus, the other three to be nodular melanomas, two of which had histopathologic features of Spitz's nevus, a phenomenon they referred to as "spitzoid malignant melanoma" (Fig. 11). About the three primary nodular melanomas, including the two "spitzoid melanomas," the Mehregans commented at length as follows:
 
"Histologically, the lesion [primary nodular malignant melanoma] shows features of a nodular malignant melanoma, including junctional activity, pagetoid epidermal invasion, involvement of the reticular dermis, marked cellular atypia, and scattered mitotic figures. . . . Spitzoid malignant melanoma in children. As a rare variant of primary nodular malignant melanoma in childhood, we discuss here a class of patients with solitary skin lesions that may or may not show clinical pigmentation, and often are difficult to recognize as malignant melanoma. Histologically, these lesions [spitzoid malignant melanomas] show features of the Spitz nevus, characterized by epidermal pseudoepitheliomatous hyperplasia, proliferation of spindle-shaped melanocytes forming junctional nests, upward transmigration of melanocytes into the epidermis, the presence of necrotic cells (Kamino bodies), dermal involvement with some degree of cellular maturation, and the presence of inflammatory cell reaction. . . . Two cases in our series each had a single clinically benign-appearing lesion and were histologically diagnosed as Spitz's nevus, in one case by two and in the second case by five dermatopathologists at different institutions. These two cases occurred in a total collection of 1,140 Spitz nevi examined in our laboratory. We have reviewed the histologic sections of the two cases, looking for some clues helpful in the identification of malignant lesions. The only feature that was present in both lesions is the number and distribution of melanocytes undergoing mitotic division. Approximately two to three mitotic figures per high-power field were present, in a wide distribution that included the full thickness of the lesions, including nests in the deep dermis well away from the dermoepidermal junction."

View Figure  		Fig. 11  Comment: What the Mehregans call "spitzoid malignant melanoma" could easily be misconstrued as Spitz nevus as judged by the findings in their figures 2a and b. On cytologic grounds alone, as assessed by conventional microscopy, it may at times be impossible to distinguish cells of "spitzoid malignant melanoma" from those of Spitz's nevus.
 
In reality, a melanoma may share features in common with a Spitz's nevus histopathologically, but no melanoma, including a so-called spitzoid one, looks exactly like a Spitz's nevus; it always fulfills criteria histopathologically and cytopathologically for melanoma because it is melanoma. Just because a histopathologist may miss the diagnosis does not mean that a "spitzoid melanoma," a "malignant Spitz's nevus," or a "metastasizing Spitz's nevus" truly is a Spitz's nevus. It is not; it is a melanoma.